Power supply system for signal receivers



Dec. 21, 1937. -B. SINGER POWERSUPPLY SYSTEM FOR SIGNAL RECEIVERS- Filed June 1, 1936 INVENTOR. ENJAMIN SING R TTORNEY.

Patented Dec. 21, 1937 PATENT emee rowan sUrrLr SYSTEM FOR SIGNAL Y nncsrvaas Beniamin- Singer, Bronx, N. Y., assignor'to Hazelthe Corporation, a corporation of Delaware Application June 1, 1936, Serial No. 82,776

9 Claims.

This invention relates to signal receivers, and more particularly to power supply systems for use a in radio broadcast receivers.

Inthe manufacture of small receivers capable I of operating from either an alternating current ordirect current. source, it is desirable to provide a power supply system of economical construction which is efficient in operation and is capable of supplying the necessary operating voltages 1. and currents to the various tubes and the sound reproducing d,vice of the receiver from either form of current source. A unidirectionally conducting device or rectifying tube is an essential element of such a system and, if this tube is to be of a cost commensurate with that of the other arrangement is utilized of paralleling the anode circuits of the tubes of the receiver and utilizing 1 the field winding of the translating device or sound reproducer as a series-connected smoothing reactor. Also, in an alternating currentdirect current receiver of this typ voltage stepup devices are not commercially feasible at the 25 present time and, accordingly, the available voltage for the plate circuits of the receiver is limited to the voltage of the source which, in practically all instances, is that of a commercially current lighting circuit, or approximately 110' volts.

80 Hence, if the field winding of the, sound reproducer is connected in series with the parallel connected plate circuits of the receiver to operate as a smoothing reactor and is designedto provide the necessary ampere turns to insure normal ileld 8B intensity in the reproducer, the voltage drop thereacross may reduce the remainingvoltage' available for application to the vacuum tube anodes to a value considerably smaller. than that necessary forsatisfactory operation. thereof unit) less the wlndingis made of such large wire as to be un'economical and to occupy an excessive space.

It is an object of the present invention, therefore, to provide an improved power supply ar- 45 rangement, for use in high-frequency signal recelvers, which isof simple and economical construction and is highly efficient in operation.

It is a further object 01 this invention to pro- .vide an improved power supply arrangement of 50 the above character which operates from either an alternating current or direct current'commercial current lighting circuit, which includes elements of standard commercial construction, and

' which is eii'ective in operation to supply substan- 55 tialiy rated voltages to the anodes ,of the several tubes included in the receiver and rated power to the translating device of the receiver.

Briefly, the above objects are attained in accordance with' the present invention by providing, in a receiver of the general type noted above,.a sound reproducing device having two field windings, one of which is connected in series with the rectifier or unidirectionally conductive device of I the power supply system and the parallel related anode circuits of the receiver across the source of current supply, and the other of which is con nected in the common path of the input and output circuits of one of the tubes of the receiver to operate as the cathode-biasingelement for this tube. The latter winding is proportioned to provide the correct bias on the associated cathode and the two windings are proportioned in size so that together they comprise the necessary number of ampere turns to provide suflicient 'magnetic field strength in the sound reproduce'r for satisfactory operation thereof. By including one of the field windings in the cathode circuit of one of the tubes, the portion of the available voltage absorbed'by the field winding is reduced without impairing the operation of the reproducer. The novel features which are believed to be characteristic of this invention are set forth with particularity in the appended claims; The invenv tion itself, however, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to. the specification taken in connection with the accompanying drawing, in which Fig. 1 illustrates a radio receiver of the well-known. superheterodyne type embodying the present invention, and Figf'2 illustrates a modiilcation of the invention.

Referring more particularly to Fig. 1 of the drawing, the invention is illustrated in its application to a radio receiver of the superheterodyne type. The receiver comprises a radio-frequency amplifier and'modulator tube Ill having its input circuit ll coupled to an antenna circuit l2 and its output circuit is coupled to the input circuit ll of a detector 1| 5. Volume control is obtained by the provision of an adjustable control grid biasing circuit for the tube III which comprises an adjustable resistor it having its active. portion shunted by a condenser I|.- A leak resistor ll paralleled by a condenser I! is provided in the input circuit of the detector II in the conventional. manner. A local oscillator, indicated generallyat 20, is provided which comprises the oscillator section of the pentagrid converter It, a

I tunable oscillation circuit 22 and afeed-back cir- 55 'from an alternating current source.

cult including an inductor 23. The tuning elements of the selector circuit ii and the local cscillation circuit 22 are ganged for unicontrol adjustment, as indicated by the dotted line 25. The output circuit-of the detector i5 is coupled by means of a condenser 26, a resistance 21 and a condenser 23 to the input electrodes of an audiofrequency amplifier tube 23 having its output circuit, in turn, coupled through a transformer 30 to the signal coil of a sound reproducing or translating device, indicated generally at 3|. The sound reproducing device 3! is provided with two field windings 32 and 33 which are connected in a power supply system indicated generally at 34, constructed and arranged in accordance with the present invention,'and are proportioned in size in a particular manner to be hereinafter described.

Screen grid and anode potentials are supplied to the tubes from the power supply system 34 through a common circuit lead 35, voltage dropping resistors 33, 31 and 33, and the inductor 23.

Considering the operation of the receiver as a whole, without regard to the details of the power supply system 34 per Se, the desired received signal wave is selected in the radio-frequency selector Ii, and is converted to an intermediate frequency in the modulator tube ID. The modulated intermediate-frequency carrier wave thus produced is further selected in the circuits l3 and I4, is detected in the detector l5, and the signal-frequency components thereof are amplified in the audio-frequency amplifier 29 and reproduced by the sound reproducer or translating device 3|.

Referring now more particularly to the power system 34, which is arranged in accordance with the present invention, the system comprises input terminals 40 and 4! which are adapted to be connected to a source of current (not shown). Connected in series with the reproducer field winding 33 between the terminal 40 and the common screen and anode circuit lead 33 is a rectifier tube 33. The circuit between each of the anode circuits of the system and the current supply terminals 43 and 4| is completed by the connection of the terminal 4! to ground, whereby a current path is established between this terminal and the respective cathodes of the several tubes. For the purpose of interrupting the supply of current to the receiver, a switch 42 is provided in the connection between the terminal 43 and the rectifier 33. The cathode heaters for the several tubes of the receiver and the tube 33 of the power supply system are connected in series with each other, and with a voltage dropping resistor 43 between the terminal 4| and one terminal of the switch 42. In order to bias the cathode of the audio-frequency amplifier tube 29 to the proper potential relative to its associated control grid, the second field winding 32 of the sound reproducing device 3! is connected between this cathode and ground. and, as thus connected, this winding is energized by the space current of the tube 23. Suitable filter condensers 44 and 45 are provided in addition to the winding 33 for smoothing the rectified output from the tube 33 when the terminals 40 and 4| are connected to supply power to the receiver frequency by-pass condenser. is also connected between the terminal 40 and ground.

In describing the operation of the power supply system, it will first be assumed that the terminals 40 and 4| are connected to an alternating current source. As thus connected and withthe A highswitch 42 closed, alternating current supply is exactly the same.

The economy of construction resulting from the use of a rectifying device 33 having a low current rating has previously been mentioned, as have also the requisites of minimizing the voltage drop between the current source and the anodes of the tubes and of providing an adequate number of ampere turns in the field windings of the reproducing device for insuring the production of a normal magnetic field strength therein, without the use of an inordinate amount of copper. These three desirable features are all attained, in accordance with this invention, by the arrangement described above, and by a proper selection of the number of turns of the field windings 32 and 33. In this connection, it will be understood that the current rating of the rectifier tube 39 is determined by. the sum of the space currents of the several tubes of the receiver, since the anode circuits of these tubes in parallel de-- termine the magnitude of current to be drawn from the source through this tube. The number of turns in the winding 32 and the size of the conductor used are chosen so that the voltage drop across this winding caused by the space current of the tube 29 produces the correct positive bias on the cathode relative to the control electrode of this tube. The winding 33 is proportioned to provide the required amount of smoothing reactance and the required, number of field ampere turns without causing an unduly large voltage drop between the voltage supply source and the tube anodes, orusing an excessively large size of conductorin the winding. The correct proportioning of this winding for a particular circuit design may best be worked out experimentally by striking a compromise between the several factors noted.

While it will be understood that the'circuit specifications may vary according to the design of a particular'application, the following specifications of the circuit elements of Fig. 1 are included'by way of example, as having been found satisfactory Referring now'to Fig. 2 of the drawing. there illustrated a modification of the invention which differs from that of Fig. 1 only in the addition of a voltage dividing or bleeding resistor 46' connected between the high potential terminal of the winding 32 and the low potential terminal of the winding 33, and having connected thereto a lead 41 for supplying a positive potential of the correct value to the screen electrodes of the tubes drawn by the bleeding resistor 46 increases the. magnitude of current through the winding 32 and nthis increase in current permits a decrease in the size of the field windings 32 and 33 without impairing the operation of the reproducer or the receiver circuit. This fact is emphasized by the f following specifications for the sound reproducer field windings when used in conjunction with a resistor 46' of 2500 ohms, the other circuit specifications being the same as those given above:

Winding -32 325o turns No. s4 wire 325 ohms Winding 33 6150 turns N0. '34 wire 450 ohms It will be observed that, in either of the two modifications described above, the use'of the winding 32 in the cathode circuit of the tube 29 eliminates a separate cathode-biasing element from the receiver and, accordingly, eliminates one item of the cost of construction. I will also be observed that, with the windings 3 and 33 connected .so that the magnetic fields produced thereby are additive, the windings are so poled with respect to each other as to prevent oscillation in the circuit of the amplifier 29 due to the so coupling between these windingsf,

present considered preferred embodiments of this invention, it will be obvious to those skilled inthe art that various changes and modifications may be made therein-without departing from this in- 88 vention, and, therefore, it is aimed in the appended claims to cover all such changes and modifications as fall within-the true spirit and scope of this invention.

What is claimed is: n

40 1. In a signal receiver, a translating device including magnetizing means, a vacuum-tube ineluding an anode, a control electrode and a oath ode, an anode-cathode circuit for said tube including a, sourceof space current and a portion of said magnetizing means connected between said anode and said source, a control electrode- While there have been described what are at tube, one of said windings beinginclu'ded in said anode-cathode circuit between said anode and said source and. the other of said windingsbeing common to saidanode-cathode and control elee trode-cathode circuits and providing a bias voltage ior said control electrode.

4; In a'signal receiver, a translating device, a vacuum tube repeater including an anode,a eontrol electrode, and a cathode, input and output circuits 'conneced to said tube including a common current path, said translating device being coupled to said output circuit. and including a pair offield windings, a pair .of power. input terminals adapted to be connected to either an alternating or direct current source of low voltage, a circuit connected to said input terminals for supplying space current to said tube and serially including a unidirectionally -conductive device and said field windings so arranged that said-windings are excited by the space current of said tube, one

of said. windings being included in saidoutput current source and the other of said windings being included insaid common path for providing a bias voltage for said control electrode.

5. In' a signal receiver, a translating device ineluding magnetizing means, a plurality of coupled vacuum tubes each including amanode, a control electrodeand a cathode; input and output circuits for said tubes, a circuit ,ior supplying power to said receiver fromeither an' alternating or direct current, source of' low voltage including a unidirectionally conductive device and said' put circuits between said anodes and said source and another portion of said magnetizing means cathode circuit for said tube, another portion 01.

3 said magnetizing means being common to said anode-cathode and control electrode-cathode for providing a bias voltage for said cdntrolelectrode.

a 2. In a signal receiver, a translating device ineluding magnetizing means, a vacuum tube insource of low voltage, an anode-cathode circuit for supplying space current to said tube from said terminals comprising, iri series between said anode and one of said terminals, a unidirectionally conductive device and a portion of said magnetizing means, a control electrode-cathode circultfor said tube, another portion of said magnetizing means being, common to said anodecathode and control electrode-cathode circuits to be energized by said space current and for providing a bias voltage for said control electrode..

eluding an anode, -a control electrode, and a cath-' ode, apair otinputtermihals adapted to be connected to either an alternating or direct current circuits to be energized by said space current and jbeing common to the input and output circuits of only one of said tubes, whereby said magnetizing means is'energized by'space current supplied netizing means provides a bias voltage for said one of said-tubes.

6. In a signal receiver, a translating device ineluding magnetizing means, a plurality of vacuum tubes, each including an anode, a control electrode and a cathode, a circuit serially including-a part oi! said magnetizing means for supplying space current tosaid tubes and for exciting said'magnetizing means, a portion or said magnetizing means being common to the anode-cathode and. control electrode-cathode circuits oi one of said,

tubes, voltage dividing means for supplying voltages to certain of the electrodes .of said tubes connected in series with said portion of said mag-' input terminals adapted'to be connected to either an alternating or direct current source of low voltage,'-and' a, circuit including the space cur-- rent paths of said tubes in parallel, said circuit including a unidlrectionally conductive ,device and one of said field windings connected in series between one of said terminals and a common connection to the anodes of said tubes; whereby n said one of "aid field windings is energized and to said tubes and said other portion ofsaid magis effective tosmooth the space current of said tubes when said input terminals are connected to an alternating current source, and the other of said field windings being common to the anodecathode and control electrode-cathode circuits of only one of said tubes, whereby it is energized by the space current flowing through said tube and the voltage developed thereacross provides a bias for said one of said tubes.

8. In a signal receiver, a plurality of coupled vacuum tubes each including an anode, a control electrode and a cathode, a translating device including a pair of field windings, a pair of power input terminals adapted to be connected to either an alternating or direct current source of low voltage and a circuit including the space current paths of said tubes in parallel, said circuit including a unidirectionally conductive device and one of said windings connected in series between one of said terminals and a common connection to the anodes of said tubes, whereby said one of said windings is energized and is eflective tosmooth the space current of said tubes when said ter-' minals are connected to an alternating current source, and the other of said field windings being common to the anode-cathode and control electrode-cathode circuits of only one of said tubes, whereby it is energized by the space current flowingthrough said tube and the voltage developed thereacross provides a bias for the control electrode of said one of said tubes, the resistance of said windings being proportioned substantially to provide normal ratedvoltage to said anodes, normal bias to said cathode, and

normal field excitation for said translating device with said terminals connected to either an alternating. or direct current source.

9. In a high-frequency receiver, a plurality of a coupled vacuum tubes each including an anode, a control electrodeand a cathode, a translating device including a pair of field windings, a pair of power input terminals adapted to be connected to either an alternating or direct current source or low voltage, a circuit including the space current paths of said tubes in parallel, said circuit including a unidirectionally conductive device and one of said field windings connected .in series between one of said terminals and a common connection to the anodes 01 said tubes, whereby said one of said windings is energized and is eflective as a smoothing reactance when said input terminals are connected to an alternating current source, and the other of said field windings being common to the anode-cathode and control elec-.

trade-cathode circuits of only one of said tubes whereby it is energized by the space current flowing through said tube, and means comprising a voltage dividing resistor connected between the low potential terminal of said one of said windings and the high potential terminal of the other of said windings for passing additional current through said other of said windings to increase the excitation thereof, the resistance of said other winding being such that the total current therethrough provides a proper bias voltage -for the control electrode of said one of said tubes.

BENJAMIN SINGER. 

